Corner bit assembly for earthmoving blades



July 22, 1969 H. GILBERTSON 3,456,370

CORNER HT ASSEMBLY FOR EAHTHMOVING BLADES Filed Sept. 21, 1967 2 Sheets-Shed l IN VILNTY )R. HERMAN GIL efRTJDN July 22, 1969 H. GILBERTSON 3,456,370

CORNER BIT ASSEMBLY FOR EARTHMOVING BLADES Filed Sept. 21, 1967 2 Sheets-Sheet INVEN R.

ATTYJ.

United States Patent U.S. Cl. 37-141 4 Claims ABSTRACT OF THE DISCLOSURE A corner bit assembly is described for attachment to earth moving blades to prevent wear and breakage of the blade. The assembly has an adapter that is rigidly secured to the blade by bolts and a readily replaceable bit. The adapter has a plurality of support fingers that extend downward, forward and outward for fitting into respective cavities formed in the back of the bit. A rib is formed on one of the end fingers for interlocking in an indentation formed in the respective cavity wall. Knockout pins passing between other fingers and the corresponding cavity wall in the bit complete the securement of the bit on the adapter.

BACKGROUND OF THE INVENTION This invention relates to blade bits for earthmoving equipment and more particularly to corner bits for earthmoving blades that are utilized on bulldozers, graders and the like.

The corners of the earthmoving blades are subjected to accelerated wear and greater forces in comparison to other areas of the blade. Generally earthmoving blades are quite expensive and represent a substantial financial loss if a blade needs to be replaced before the useful life of the earthmover is expired.

To prevent the accelerated wear and breakage of the corners of the blades, it has been customary to mount wear plates or corner bits over the blade corners to protect the blades. Frequently the wear plates or corner bits are bolted to the blade in the hopes that they can be readily removed when they are broken or show considerable wear. More often than not the bolts are deformed or rusted requiring the cutting of the bolts to remove the wear plates from the blade. To perform this task the earthmover has to be taken from the job site to a facility that has a cutting torch or alternatively bringing a cutting torch to the job site. Considerable down time is involved in cutting the corner bit or wear plate from the blade and then replacing it with a new one.

Furthermore, each wear plate or hit is quite expensive. Each has to be precision formed to be able to be precisely mounted to the wear plate. Only a small portion of the wear plate is worn away. The rest of it is discarded.

One principal of this invention is to provide a corner bit assembly that may be readily mounted to a blade corner in which the bit can be readily removed and replaced at a considerably lower cost than previous bits that have been used.

An additional object of this invention is to provide a novel two piece bit assembly, one piece of which remains on the blade and supports a second readily removable piece, most of which can be worn away before it needs to be replaced.

A further object of this invention is to provide a novel bit assembly that substantially reduces the down time required to replace the corner bits.

An additional object of this invention is to provide a bit assembly that is relatively inexpensive to manufacture, simple to mount to a blade and structurally efficient.

A still further object of this invention is to provide a two piece bit assembly having an adapter and a bit in which the bit can be readily mounted on the adapter in a structurally secure manner with a minimum of fastening devices.

An additional object of this invention is to provide a bit and adapter assembly that can be connected together to form an integral ground engaging unit for protecting the blade.

These "and other objects and advantages of this invention will become apparent upon the reading of the following description of a preferred embodiment of this invention.

BRIEF DESCRIPTION OF THE DRAWING A preferred embodiment is illustrated in the accompanying drawings in which:

FIG. 1 is a fragmentary perspective view of the front portion of an earthmover showing a corner bit assembly mounted on the corner of the earth moving blade;

FIG. 2 is a fragmentary perspective view of the bit assembly and a section of the blade with the assembly parts separated;

FIG. 3 is an enlarged sectional view taken through the assembled adapter and blade on the line 33 of FIG. 1;

FIG. 4 is a fragmentary cross sectional view taken along line 44 in FIG. 3.

DESCRIPTION OF THE PREFRR'ED EMBODIMENT This invention concerns a corner bit assembly for earthmoving blades that are attached to earthmovers such as bulldozers, scrapers, graders and the like. For purposes of illustration FIG. 1 shows a fragmentary portion of the front of a bulldozer 10 having an earthmoving blade 11 mounted in front thereof for excavating earth as the bulldozer is propelled. A corner bit assembly, generally designated by the numeral 12, is mounted on the corner of the blade for protecting the blade. The bit assembly 12 has two principal partsan adapter 14 and a bit 15.

The adapter 14 has a mounting section 16 (FIG. 2) with a bit support face 18. The section 16 is tapered, increasing in thickness from the back edge 17 toward the face 18. The mounting section 16 has its front face 18 substantially perpendicular to the blade engaging face 19 of the mounting section. Countersunk holes 20 are formed in the section 16 to match the holes 21 in the blade 11 for facilitating the attachment of the adapter 14 to the blade 11.

The bit support face 18 of the adapter is a shoulder surface that faces downward and forward when the adapter is attached to the blade. Tapered fingers 22, 23, 24 and 25 extend from the face 18 forward, downward and outward for supporting the bit 15 and aiding in transferring forces applied to the bit uniformly to the blade. As shown in FIG. 4, the fingers 22-25 are tapered with the front surface 26 and back surface 27 of each finger converging to form a bottom tip 28. The fingers 22-25 have triangular shaped side surfaces 2932 respectively that face outward toward the end of the adapter 14.

The tapered fingers 22-25 have triangular side surfaces 33-36 opposite the surfaces 29-32. The side surfaces 33- 36 are contoured to form curved corners with the bottom tips 28 for facilitating the mounting of the bit 15 to the adapter 14. The fingers 22-25 are spaced apart to receive complementary elements of the bit 15. Concavely curved surfaces 37-39 between the fingers 22-25 facilitate the snug mounting of the bit to the adapter.

A rib 40 (FIGS. 2 and 3) is formed on the finger 22 and projects outwardly from the side surface 29 for providing an interlocking element to fit within a complementary element of the bit. Indentations 41 and 42 (FIG. 2) are formed in the side surfaces 33 and 35 respectively for facilitating the securing of the bit to the adapter.

The bit 15 is tapered (FIG. 3) with a front surface 43 and a back surface 44 converging to form a bottom cutting tip 45. The bit 15 has an outer end face 46 (FIG. 2) and an inner end face 47. The outer. end face 46 and the front surface 43 intersect to form a side cutting edge 48. The bottom cutting tip 45 and the side cutting edge 48 intersect to form a curved corner 49 that represents the outermost projection of the cutting profile of the blade. The bit 15 has an upper shoulder surface 50 (FIG. 4) for abutting against the front face 18 of the adapter 14.

Finger cavities 51, 52, 53 and 54 are formed in the shoulder surface 50 for receiving respective fingers 2225. Lands 55-57 (FIG. 2 and 3) which separate the cavities, are formed to slide between the fingers 22-25. The ends of the lands 55-57 are convexly curved to snugly engage the curved surfaces 3739.

The bit 15 has an interlocking element for combining with the rib 40 to hold the bit to the adapter. The interlocking element is an indentation or groove 58 (FIG. 2 and 3) formed in the wall of the cavity 51 for receiving the rib 40 therein.

To prevent the bit 15 from being pulled from the adapter 14 when the earthmover moves rearward, scraping the bit along the ground, the fastening mechanisms are provided for secuerly holding the bit to the adapter. The fastening mechanisms include apertures 59 and 60 (FIG. 2) that extend from the front surface 43 to the back surface 44 of the bit. The apertures 59 and 60 are so aligned that they form indentations in the side walls of the lands 55 and 57. The indentations 41 and 42 in the fingers 22 and 24 of the adapter 14 and the indentations in the walls of the lands 55 and 57 form substantially circular apertures when the bit is mounted on the adapter. Knock-out pins 61 and 62 are mounted in the apertures 59 and 60 to prevent the bit from being pulled from the adapter.

To mount the bit assembly 12 to a blade one merely positions the adapter with the mounting section 16 over the lower edge of the blade 11 until the holes of the adapter are aligned with the blade holes 21. The operator then inserts bolts through the holes 20 and 21 to securely fasten the adapter to the blade. The bit 15 is then mounted on the adapter by first mounting the outermost end of the bit on the adapter so that the finger 22 slides into the cavity 51 with the rib 40 sliding into the indentation 58. Then the remainder of the bit is pivoted upwardly to slide the fingers 23, 24 and into the cavities 52, 53 and 54 respectively. The side surfaces of the fingers 22- 25 respectively are so contoured as to enable the bit to be pivoted upwardly about the pivot point determined by the location of the rib in the indentation or groove 58. In this manner, the upper shoulder surface of the bit 15 engages the lower face 18 of the adapter to prevent movement of the bit with respect to the adapter.

To prevent the bit from being pulled away from the adapter the knock-out pins 61 and 62 are inserted through the apertures 59 and to lock the fingers 2 2 and 24 in their respective finger cavities. It should be noted that the knock-out pins have a central rubber section that provides a certain amount of resiliency in the knock-out pins to facilitate their removal.

When the bit becomes worn, it can easily be removed and replaced by punching out the knock-out pins and pivoting the bit downwardly and outward. Then a new bit can be easily mounted on the adapter without any special tools and in a minimum of time.

The wedge shape of the adapter 14 in cross section provides a substantial front face 18 to receive the thrust of the bit 15. This also helps to point the tapered fingers at the most advantageous angle to provide adequate strength as the bit wears away. The broken line XX indicates roughly the line to which the bit wears before it becomes too weak. Substantially more than half the volume of the bit can be worn away before replacement.

The fingers are pointed in a direction substantially parallel to the outer end faces of the adapter and the bit. The greatest thrusts are against the outermost corner of the bit. By directing the fingers thisway, these thrusts are better distributed to the adapter 14 from the bit.

It should be understood that the above described embodiment is simply illustrative of the principles of this invention and numerous other embodiments may be readilly devised by those skilled in the art that encompass the principles of this invention and fall within the scope thereof. Therefore, only the following claims are intended to define this invention.

1. A corner bit assembly for an earthmoving blade comprising:

(a) a support adapter mounted on the lower front corner face of said earthmoving blade, said adapter having an outer support finger and a plurality of inner support fingers extending downward and outward;

(b) a bit mounted on the support adapter having a complementary outer finger cavity and a plurality of inner finger cavities with walls formed therein receiving the respective outer and inner adapter support fingers;

(c) said outer support finger and cavity having an interlocking complementary side rib (40) and the indentation (58) to hold the bit to the adapter;

(d) said =bit having one or more apertures extending therethrough intersecting the walls of one or more of the inner cavities and the sides of one or more of the inner fingers; and

(e) a knockout pin mounted in each aperture engaging a cavity wall and an inner finger to force the bit laterally on the adapter to securely maintain the rib (40) in the indentation (58) to prevent separation of the fingers from the cavities.

2. A corner bit assembly for an earthmoving blade as defined in claim 1 wherein the knockout pin has a resillient section for biasing the bit laterally on the adapter and for permitting the easy removal of the knockout pin from the aperture.

3. A corner bit assembly for a blade of an earthmoving vehicle such as a bulldozer, grader and the like, said assembly comprising:

(a) a support adapter for mounting to one of the lower corners of the blade, said adapter including (1) a wedge shaped blade mounting adapter that includes a rear face that seats on the lower front face of the blade, the adapter having bolt holes aligned with bolt holes in the blade for facilitating the rigid attachment of the adapter to the blade;

(2) the adapter having a front face facing downward and forward when the adapter is attached to the blade and a plurality of parallel tapered fingers extending from said front face in an inclined outward angle to the front face, and wherein the outermost finger has a side rib (40) formed thereon;

(b) a bit form removably attaching to the adapter, said bit having an upper rear face (50) for abutting the adapter front face and a plurality of tapered finger cavities for receiving respective adapter fingers in which the outermost finger cavity (51) has a side indentation (58) for receiving the finger side rib and wherein the cavities have a configuration such that the bit is mounted to the adapter by first positioning the outermost end of the bit on the adapter References Cited With the finger side rib (40) in the bit cavity in- UNITED STATES PATENTS dentation (58) and then secondly pivoting the other 1 803 654 5/1931 Ronk 214 145 end of the bit on the adapter so that the fingers slide 2732639 1/1956 X intothfiirrespecfive cavifiwand 5 2:965:9'89 12/1960 Hibbaid 37*141 X (c) resilient knock-out pins mounted in apertures 3,029,534 4/1962 Rakisits formed in the bit and adapter fingers to prevent the 032 9 1 5 19 2 Dils 37 141 inadvertent removal of the bit from the adapter. 3,039,2 1 5 19 3 Plath 37 113 4. A corner bit assembly as defined in claim 3 wherein 3,160,967 12/1964 Niehcfls 37-441 one side surface of each finger is contoured to permit the 10 pivotal movement of the bit to slide the fingers into the EDGAR BURRPnmary Exammer cavities so that the upper rear face (50) of the bit abuts against the front face (18) of the adapter. 37 61, 72; 2g5 261 

